Al-Si 합금의 마멸특성에 (磨滅特性) 미치는 조성의 영향

권혁무,장충근,신세균 ( Hyuk Moo Kwon,Choong Kun Chang,Se Kyoon Shin ) 한국주조공학회 1986 한국주조공학회지 Vol.6 No.1

The Wear Characteristics of Al-Si alloys were investigated with various Si contents by using the not-dispersed alloys and uncoated-graphite dispersed alloys. Uncoated-graphite dispersions were accomplished by Vortex method carrying 1 hr. heating at 400℃ on uncoated-graphite. Wear loss were increased by increasing Si contents at the elevated final load. Hyper-eutectic alloys showed higher wear resistance values at the small final load of 2.1㎏ and 3.2㎏, but at the more increased final load, hypo-eutectic alloys showed higher wear resistance values than hyper-eutectic alloys. The property of wear resistance of uncoated-graphite dispersed Al-Si alloys showed more good values than not-dispersed alloys. This peroperty of increased war resistance were resulted from lubricating action of dispersed graphite.

흑연을 분산시킨 Al-Si 합금의 유동성에 (流動性) 관한 연구

권혁무,신세균,장충근,최승평 ( Hyuk Moo Kwon,Se Kyoon Shin,Choong Kun Chang,Seung Pyung Choi ) 한국주조공학회 1987 한국주조공학회지 Vol.7 No.1

The spiral fluidity of graphite-dispersed Al-Si alloys has been investigated as a function of contents of Si and graphite, and of particle size of graphite. The dispersion of uncoated graphite is carred out by the vortex process of preheat-treated graphite into molten metal. The fluidity of hyper-eutectic Al-Si alloys is observed to the better than that of hypo-eutectic ones. In the case of graphite-dispersed Al-Si alloys they fluidity increases in hypo-eutectic alloys and decreases in hyper-eutectic ones in comparison with that of the corresponding undispersed alloys. Fluidity decreases with an increase of amount of dispersed graphite particles and inversely proportional to the total surface area of graphite particles.

Al-Si 합금의 CFR 과 MDE 에 미치는 냉각속도의 영향

권혁무,김수영 ( Hyuk Moo Kwon,Soo Young Kim ) 한국주조공학회 1984 한국주조공학회지 Vol.4 No.4

In order to clarify the solidification mechanism of Al-Si alloy, Mushy Degree of Eutectic Solidification (MDE) and Centerline Feeding Resistance (CFR) were systematically studied by casting with various compositions of Al-(6∼18%) Si alloys into several kinds of molds having different cooling rates. The results are as follows: 1. CFR% increases slightly as solute concentration increases, but decreases remarkably as the cooling rate of the mold increases, that is, the composition dependence of the alloys has more effect on the change of CFR% than that of the mold cooling rate. 2. The composition dependence of MDE value has the same tendency as that of Degree of Eutectic Solidification (DES). MDE value within the range of hypereutectic composition is larger than that of hypoeutectic and it represents the maximum value at eutectic composition. The higher the cooling rate is, the less the MDE value is.

Infectious bursal disease virus(국내분리주)의 variable VP2 gene의 분석

권혁무,김대규,성환우,Kwon, Hyuk-moo,Kim, Dae-kyu,Seong, Hwan-woo 대한수의학회 1999 大韓獸醫學會誌 Vol.39 No.3

A 474-base pair segment covering the hypervariable region of VP2 gene from six Korean infectious bursal disease virus(K-IBDV) isolates(K1, K2, SH/92, 225, 269, 310) and one attenuated IBDV(DAE) were amplified using RT-PCR, sequenced, and compared with published sequences for IBDV. K-IBDV isolates(K1, K2, SH/92, 225, 269) and foreign very virulent(vv) IBDV strains had 94.93~100% amino acid sequence similarity. K-IBDV isolate 310 and other K-IBDV isolates had 84.31~86.07% amino acid sequence similarity. Attenuated strain(DAE), like other attenuated strain, has substitution at positions 279(D to N) and 284(A to T) as well as in the serine-rich heptapeptide region. Five K-IBDV isolates except 310 isolate share unique amino acid residues at positions 222(A), 256(I), 294(I) which are not present in other standard and attenuated strains. At the two hydrophilic region, K-IBDV isolates except 310 isolate had identical amino acids comparing with Belgium vv IBDV 894VB but had four amino acid substitutions comparing with Chinese vv IBDV F9502. The SWSASGS heptapeptide is conserved in all K-IBDV isolates. The sequence of K-IBDV isolate 310 was markedly different from other IBDV strains, evolving from a separate lineage than the others. By phylogenetic analysis, Five K-IBDV isolates except 310 isolate were categorized in one group with foreign vv IBDV isolates but K-IBDV isolate 310 was categorized in a separate group which was differentiated from other compared IBDV strains.

돼지 전염성 위장염 바이러스(국내분리주)의 분자생물학적 특성 규명

권혁무,피재호,Kwon, Hyuk-moo,Pi, Jae-ho 대한수의학회 1998 大韓獸醫學會誌 Vol.38 No.2

Sixteen Korean field transmissible gastroenteritis viruses (TGEVs) were isolated using swine testicular cell (STC) and the genomic diversity of them was analyzed. All TGEV isolates produced a typical cytopathic effect in STC and were confirmed as TGEV by immunofluorescence assay using monoclonal antibody against TGEV and PCR using TGEV specific primers. RNAs from TGEV field isolates and vaccine TGEV were extracted and amplified by RT and PCR. The RT-PCR products were digested with selected restriction enzymes and analyzed RFLP patterns. The N-terminal end region of S gene and ORF 3 and 3-1 genes of TGEV amplified by TGEV specific primer pairs seemed to be conserved. Most specific variations were detected in S gene amplified by TGEV 4/6 primer pairs which includes antigenic sites A and D. When the PCR products were treated with Sau3AI and Ssp I, Bvac(vaccine strain), field isolates 133 and 347 were differentiated from Miller and Purdue types. In the case of D5 field isolates, it was classified into Purdue type by Sau 3AI but classified into independent TGEV by Ssp I. Two different TGEV strains from D2 sample were confirmed by plaque purification and RT-PCR-RFLP analysis. To investigate the change occurring in TGEV genome after serial passage, the TGEV P44 strain was passaged through STC. There were specific changes in S gene and a large deletion was observed in ORF 3 and 3-1 genes. These studies showed that a distinct difference in genome exists among TGEV field isolates.

국내분리 돼지 전염성 위장염 바이러스의 antigenic site A와 D를 포함하는 spike gene의 염기서열 분석

권혁무,피재호,성환우,Kwon, Hyuk-moo,Pi, Jae-ho,Seong, Hwan-woo 대한수의학회 1998 大韓獸醫學會誌 Vol.38 No.2

The nucleotide sequences of spike (S) glycoprotein containing antigenic sites A and D of TGEV isolated in Korea were determined and compared with published sequences for TGEVs. The TGEV 133 and DAE5 strains had 97.40% nucleotide sequence similarity. The overall nucleotide sequence similarity of the 133 and DAE5 strains compared with other TGEV strains was between 96.86% and 99.15%. The similarity of the predicted amino acid sequence of the 133 and DAE5 strains was 94.93%. The TGEV 133 and DAE5 strains had 94.93-98.61% amino acid similarity with published sequences of other TGEV strains. The sequences of amino acid codons in the antigenic sites A and D were identical among all the viruses although there were several nucleotide changes in region containing antigenic sites A and D of Korean TGEV isolates. By phylogenetic analysis of the sequences, two Korean isolates 133 and DAE5 seemed to be derived from different lineages. These studies showed that a distinct difference in genome exists among TGEV field strains isolated in Korea.

PCR과 RFLP분석을 이용한 transmissible gastroenteritis virus의 spike glycoprotein gene과 nonstructural protein gene의 분석

권혁무,Kwon, Hyuk-moo 대한수의학회 1996 大韓獸醫學會誌 Vol.36 No.3

To analyze the genomic diversity of transmissible gastroenteritis virus (TGEV), the N-terminal half of the spike (S) glycoprotein gene and nonstructural protein gene (open reading frames 3 and 3-1) were amplified by reverse transcriptase reaction and polymerase chain reaction (RT-PCR), and analyzed using restriction fragment length polymorphism (RFLP) patterns of the amplified DNA. In this study, TGEV Miller (M6) and Purdue (P115) strains were used as reference strains, and two vaccine strains (MSV and STC3) and four Korea isolates (P44, VRI-WP, VRI-41, and VRI-48) were analyzed. All TGEV strains were amplified with three TGEV primer pairs. Although there was some exception in RFLP analysis, this method differentiated TGEV strains into following groups : Miller group (M6 and MSV), Purdue group (PUS, STC3, P44, VRI-WP, VRI-41, and VRI-48). Using Sau3AI and SspI, VRI-48 was differentiated from the Miller and Purdue type viruses. The RT/PCR in conjuction with RFLP analysis was a rapid and valuable tool for differentiating several strains of TGEV. This study revealed the occurences of distinct difference in genome of TGEV strains.

RT/PCR과 RFLP 분석에 의한 Infectious bursal disease virus(국내분리주)의 특성 규명

권혁무,김대규,성환우,Kwon, Hyuk-moo,Kim, Dae-kyu,Seong, Hwan-woo 대한수의학회 1999 大韓獸醫學會誌 Vol.39 No.1

Field infectious bursal disease viruses (IBDVs) were isolated from IBDV-suspected commercial chickens. The variable region in VP2 gene of six Korean IBDV isolates (K-IBDVs) and IBD vaccines was examined using the reverse transcriptase / polymerase chain reaction-restriction fragment length polymorphism (RT/PCR-RFLP) assay. With all K-IBDVs and vaccine IBDVs, a 474-bp fragment of the VP2 gene was amplified and tested with various restriction enzymes. Restriction enzymes BstNI and StyI differentiated K-IBDV isolates and IBD vaccines into four groups. Restriction enzyme profiles of K-IBDV isolates were different from them of IBD vaccines. K-IBDV isolates except for 310 isolate had specific SspI and TaqI recognition sites, which were recognized in highly virulent IBDVs, but IBD vaccines had no those sites. This study showed that RT/PCR-RFLP assay was thought to be valuable tool for differentiation of IBDVs and identification of highly virulent IBDV.

질화철의 경도에 미치는 탄소와 규소의 영향

장충근,권혁무 충남대학교 자연과학연구소 1979 學術硏究誌 Vol.6 No.2

The effect of carbon and silicon on the hardness of nitrided iron at the temperature range of 650℃- 850℃ was investigated, In the case of carbon added iron, the peak hardnesses and surface hardness were increased but the thickness of nitrided layer was decresed than the nitrided pure iron, In the case of silicon added iron, the internal hardness and surface hardness were decreased than the carbon added iron.

분자유전학적인 방법을 이용한 닭 전염성 기관지염 바이러스의 혈청형 감별

권혁무(Hyuk Moo Kwon),Mark W. Jackwood(Mark W. Jackwood),Jack Gelb Jr.(Jack Gelb Jr.) 한국가금학회 1996 한국가금학회 정기총회 및 학술발표회 Vol.13 No.-